sberry
Banned
Pipe under slab. How hard is it to drive pipe under a slab, say 20 ft for electric pipe? I know you can even hook air comp up for it and some guy round here has a career of adding drains to floors after the fact.
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Pipe under slab.
- Thread starter sberry
- Start date
It all comes down to what type of material you are trying to push through. We do it with ductile iron pipe occasionally to get under as sidewalk or driveway.. For water services we use a mole. You can rent them. EMT probably won't take the force required to push it 20 feet.
https://www.sunbeltrentals.com/equipment/items/1435/trenchless-boring-tools/
https://www.sunbeltrentals.com/equipment/items/1435/trenchless-boring-tools/
i have washed a pipe under a slab before - always worried about the slab not being supported afterwards - 20 feet isn't that far to wash a hole followed by tunneling by hand then backfilling and compacting - work from both ends - should be able to do it in a day
cbacres
Well-known member
If material loose enough, try hooking a decent vacuum to it.
I've driven conduit this way before.
Drive some, **** soil, drive, etc.
You may want to consider Ridgid conduit for in the ground.
I've driven conduit this way before.
Drive some, **** soil, drive, etc.
You may want to consider Ridgid conduit for in the ground.
Flail
Well-known member
Depends on what’s under the slab. When gas co tried pounding a conduit under hiway front of my house, I told them no way. I was right, the subsoil is cobble. Their point popped out through the pavement. They had to trench the hiway. My shop would be no problem. There is 6” compacted gravel under the slab.
VOH
Well-known member
if its a softer soil, why not use a heavy-walled steel pipe, like a piece of oil field pipe, with a point welded to it. Drive it in to the inside. when its to where you want, drill into the side to get to the wire. heck, even a small auger point on it to help "pull" it while driving it.
rustyzman
Well-known member
My Great Uncle the Plumber used to connect a garden hose to the pipe and work it under sidewalks, roads, etc with pipe wrenches by hand while under water pressure. Never heard a later complaint about his work or issues with the structures he went under. Bear in mind he was a Very Stout guy so the hand labor involved was not an issue for him. Obviously won't work through rock.
When I was a kid my dad would take me to work on occasion installing natural gas services. They used a hydraulic pipe pusher.
A trench was dug to the gas main then the pusher was lowered into the trench. It had jack screws on the sides that pushed against the sides of the trench to level, aim and set the unit. 4' sections of solid 1 1/2" steel rod were grabbed by a type of collet and pushed into the ground. When the ram bottomed out, it was withdrew and a new section of 4' rod was screwed to the end and repeated. The operator could hit another 3'x4' trench by the house 100' to 200' away. Once at the target the gas pipe was fastened to the steel rods and pulled back to the main.
Not sure if they rent this stuff or not. You may be able to just line up some drill rod and push it through with a truck or other heavy equipment if you had a way to guide it like dig a trench up to the slab and bury a 20' length of schedule 40 pipe and use that as a guide to push drill rod through.
A trench was dug to the gas main then the pusher was lowered into the trench. It had jack screws on the sides that pushed against the sides of the trench to level, aim and set the unit. 4' sections of solid 1 1/2" steel rod were grabbed by a type of collet and pushed into the ground. When the ram bottomed out, it was withdrew and a new section of 4' rod was screwed to the end and repeated. The operator could hit another 3'x4' trench by the house 100' to 200' away. Once at the target the gas pipe was fastened to the steel rods and pulled back to the main.
Not sure if they rent this stuff or not. You may be able to just line up some drill rod and push it through with a truck or other heavy equipment if you had a way to guide it like dig a trench up to the slab and bury a 20' length of schedule 40 pipe and use that as a guide to push drill rod through.
HoosierBuddy
Well-known member
I've worked with or hired about every type of equipment available to make bores. Everything from slamming a pipe under a sidewalk with a sledgehammer, manual jacks, pneumatic boring, hydraulic jacking, hydraulic boring, and various types of directional boring machines.
For your purpose, assuming decent soil conditions (which is ALWAYS a crapshoot)...I'd recommend a pneumatic mole. You'll have to rent the mole and an air compressor.
Or...hire someone to do it. Or...saw out the concrete, lay the conduit and then fix it.
That last one is the only one that is guaranteed to work. Sometimes you can't get a bore in and cutting out the pavement/concrete is the only way.
ONE MORE THING!!!!
Make sure to get your utilities located. If there's already a gas line or water line under that slab that you'll need to cross...DO NOT ATTEMPT TO BORE. You'll have to cut the concrete out of the way.
Phil
For your purpose, assuming decent soil conditions (which is ALWAYS a crapshoot)...I'd recommend a pneumatic mole. You'll have to rent the mole and an air compressor.
Or...hire someone to do it. Or...saw out the concrete, lay the conduit and then fix it.
That last one is the only one that is guaranteed to work. Sometimes you can't get a bore in and cutting out the pavement/concrete is the only way.
ONE MORE THING!!!!
Make sure to get your utilities located. If there's already a gas line or water line under that slab that you'll need to cross...DO NOT ATTEMPT TO BORE. You'll have to cut the concrete out of the way.
Phil
I guess you could get a piece of 2" steel pipe, make a point and hard face it. If you drilled a couple holes just behind the point and put water to it, it "may," being persuaded by a BFH and pipe wrenches go through. Then you have to locate it. Once it is under the slab how do you do that?
homebuilt burner
Well-known member
We have used a Borzit. Check it out.
toplessHO
Well-known member
20 ft is good enough to use chain link fench top rail for a sleeve
will need a ditch leveled out 20ft back
can start with a shorter piece,pull it out and replace with the longer one.
this is used only as a sleeve,put real conduit inside when done
will need a ditch leveled out 20ft back
can start with a shorter piece,pull it out and replace with the longer one.
this is used only as a sleeve,put real conduit inside when done
willymakeit
Well-known member
This, works wellIt all comes down to what type of material you are trying to push through. We do it with ductile iron pipe occasionally to get under as sidewalk or driveway.. For water services we use a mole. You can rent them. EMT probably won't take the force required to push it 20 feet.
https://www.sunbeltrentals.com/equipment/items/1435/trenchless-boring-tools/
ovrrdrive
Well-known member
At 20' I'd just find an underground contractor and have them come missile it. If you can find a utility contractor working nearby they would probably do it for a few hundred bucks. A directional bore would be best but it would be a bit more expensive. Any crew that has done it a few times should be able to keep a missile flat for 20 feet.
Never, ever flush out a pipe under your driveway unless you want to have the driveway crack later.
Never, ever flush out a pipe under your driveway unless you want to have the driveway crack later.
Been about a month, did you get anything figured out ? Your shop ? Why not up and over ?